The present invention relates generally to the handling of crankcase gases (which are presently vented to the atmosphere) in a more environmentally friendly manner. More specifically, the present invention relates to the use of an accumulator for the temporary storage of crankcase gases and a pressure difference-based flow system which transfers such gases to the intake manifold to be burned as part of the normal engine combustion cycle within the cylinders.
At the present time, internal combustion engine emissions are subject to regulations promulgated or issued by the EPA and CARB. These emissions regulations are directed generally to tailpipe or stack exhaust. There is, however, another source of what could be termed harmful emissions, and this includes the gases in the crankcase which are currently vented directly to the atmosphere. Venting of such gases is important in order to prevent an unacceptable pressure buildup within the crankcase. These crankcase gases may be a mixture of "blowby" gases and vaporized oil and oil mist. Blowby gases are typically the result of combustion gases and air that get past the piston rings into the crankcase. These gases may pick up significant amounts of engine oil, which often drips on the ground, despite the use of gas/oil separators at the crankcase exit. The oil content of such gases is significant even without visible dripping. There are likely trace amounts of other gases, but regardless of the exact composition and proportions, these crankcase gases which enter the atmosphere are not what would be considered to be environmentally friendly. Consequently, it is anticipated that new federal and CARB emissions regulations will not allow the discharge of these gases to the atmosphere to continue. It is anticipated that new emissions regulations will require the inclusion of crankcase gases as part of regulated diesel engine emissions.
If, in fact, such regulations are promulgated, some system will be required in order to prevent the venting of crankcase gases directly to the atmosphere. Some type of treatment or filtering will be required, though no specific designs prior to the present invention are known to provide an adequate solution. Until such time as regulations are actually promulgated, there is only speculation as to what emissions levels may be specified for each type or category of pollutant. However, if the crankcase gases are burned by combustion within the engine cylinders, the resulting emissions should then be governed by the present EPA and CARB emissions regulations.
Therefore, the present invention is directed to a system, with various embodiments, which is capable of first capturing the crankcase gases rather than venting them directly to the atmosphere and then cycling those gases into the intake manifold where they are mixed with inlet air and burned in the cylinders. Effectively, this will result in substantially reducing, if not virtually eliminating, the unburned hydrocarbons from the crankcase gases. The present invention uses existing engine pressure differentials to transport the crankcase gases to anti from a two-chamber accumulator.
While earlier crankcase ventilation systems are known to exist, none are believed to be directed to the specific approach contemplated and provided by the present invention. The following patent references are believed to be a representative sampling of such earlier-crankcase ventilation systems:
______________________________________ ISSUE PATENT NO. PATENTEE DATE ______________________________________ 4,167,164 Bachmann Sep. 11, 1979 4,557,226 Mayer et al. Dec. 10, 1985 4,901,703 Humphries Feb. 20, 1990 5,205,265 Kashiyama et al. Apr. 27, 1993 ______________________________________